We don’t know exactly when it might happen, but setting up a colony on Mars clearly lies ahead in humanity’s plans. Elon Musk sees 2029 as the earliest date, while most researchers believe this won’t happen before 2050 at the earliest. But, in the meantime, it’s not too soon to start thinking about how many people would be needed to get a colony up and running.

In a new study, yet to be peer-reviewed, researchers from George Mason University found that only 22 people would be needed to set up a colony on Mars. This is a much lower number than in other studies. Previously, researchers suggested that you’d need at least 100 people. But the authors of a new study claim their assumptions are more realistic than previous studies.

“We tend to often treat humans as just numbers or particles devoid of personal incentives, heterogeneity and adaptability,” Anamaria Berea, study author and computational and data sciences professor, told The Register. “Human groups are complex systems where the outcome is not the sum of its parts, but synergistic.”

Debunking previous estimates

In 2022, a research paper concluded that 110 humans would be needed to set up a self-sustaining colony on Mars. But this is far from being the only estimate. In 2003, a study suggested 100 people would be needed. Just a bit earlier, in 2001 another paper put the colony size at 100. However, this may be more than necessary, a new study found.

Berea and her team at George Mason University said the previous papers didn’t consider the social and psychological aspects of colony starters. They also said that previous research didn’t consider the colony interactions in space. “Twenty-two is acceptable when shipments from Earth are possible for resupply. It might even be lower,” Berea explained to The Register.

To find more realistic answers, the researchers created a model that simulated a Mars colony. Specifically, this simulation focused on how many people are needed to create a viable colony. The researchers also looked at which features would contribute to its success. They used data from previous studies, such as surveys completed by astronauts at the International Space Station.

Researchers ran five simulations, each of which modeled 28 Earth years of colony life. For each simulation, they changed factors such as the number of people and different personalities. They found that 22 was the minimum needed for a colony. Ultimately, the team also found that people with agreeable personalities were most likely to thrive in the colony and help its overall survival.

Agreeable colony starters

The agreeable personality trait is one of the five major dimensions in the Five Factor Model of personality, also known as the Big Five personality traits. This model is often used in psychology to describe human personality and is a widely accepted framework for understanding personality differences.

Agreeableness refers to the degree to which a person is kind, cooperative, compassionate, and considerate. People high in agreeableness tend to be more trusting, empathetic, and willing to help others, while those low in agreeableness may be more skeptical, critical, or competitive.

The model further suggested that those with neurotic and competitive personalities were more likely to fail the mission and die earlier. Consequently, this also risked the success of the overall mission. “Martians with the neurotic psychology and a high coping capacity benefit the least from interaction with other Martians,” the researchers wrote in their paper.

It’s always hard to predict how humans will behave. This is especially true in such a different and challenging environment. But overall, the study provides valuable information. This data could be applicable when are ready to send humans to Mars and possibly colonize the planet. The study highlights how important it is to focus on the implications of distinct personalities and how such personalities interact. We may or may not start a colony on Mars in the next few years — but it can’t hurt to be prepared.